| EUS | endoscopic ultrasound; external urethral sphincter |
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| GES | gastroesophageal sphincter; glucose-electrolyte solution |
| GUS | genitourinary sphincter; genitourinary system |
| IAS | immunosuppressive acidic substance; infant apnea syndrome; insulin autoimmune syndrome; interatrial ... |
| ICS | ileocecal sphincter; immotile cilia syndrome; impulse-conducting system; integrated case study; inte... |
| third tonsil | A collection of more or less closely aggregated lymphoid nodules on the posterior wall and roof of the nasopharynx, the hypertrophy of which constitutes the morbid condition called adenoids. Synonym: tonsilla pharyngealis, tonsilla adenoidea, Luschka's gland, Luschka's tonsil, third tonsil. (05 Mar 2000) |
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| third trochanter | An occasional process at the proximal end of the lateral lip of the linea aspera of the femur, about on a level with the lesser trochanter, giving insertion to the greater part of the gluteus maximus muscle. See: gluteal tuberosity. (05 Mar 2000) |
| third ventricle | A narrow, vertically oriented, irregularly quadrilateral cavity in the midplane, extending from the lamina terminalis to the rostral opening of the mesencephalic aqueduct. This ventricle communicates at its rostrodorsal corner with each of the two lateral ventricles through the left and right interventricular foramen of Monro. Its narrow roof is formed by the tela choroidea which is attached on either side to the tenia thalami; its lateral wall by the medial surface of the thalamus and, below the hypothalamic sulcus, by the hypothalamus which also forms its floor. In lateral profile, the third ventricle exhibits a number of recesses: in its floor, from before backward, 1) the preoptic recess in the acute angle between the base of the lamina terminalis and the dorsum of the optic chiasm, 2) the infundibular recess extending ventrally into the infundibulum but (in humans) not into the hypophysial stalk, and 3) the mamillary or inframamillary recess caused by the protrusion of the mamillary bodies into the ventricle. From its dorsocaudal corner, the pineal recess extends caudally into the pineal stalk. Synonym: ventriculus tertius, diacele, ventricle of diencephalon. (05 Mar 2000) |
| third ventriculostomy | An operation to establish an opening from the third ventricle to the prechiasmal and interpeduncular cisterns (Stookey-Scarff operation) or from the third ventricle to the interpeduncular cistern (Dandy operation). (05 Mar 2000) |
| anal sphincter | See: external anal sphincter, internal anal sphincter. (05 Mar 2000) |
| anatomical sphincter | An accumulation of muscular circular fibres or specially arranged oblique fibres the function of which is to reduce partially or totally the lumen of a tube, the orifice of an organ, or the cavity of a viscus; the closing component of a pylorus. (05 Mar 2000) |
| annular sphincter | A short thickening of circular muscular fibres, similar to a ring; a ring-shaped sphincter as opposed to a segmental sphincter. (05 Mar 2000) |
| antral sphincter | Angular sphincter, thickening of the circular muscular layer forming a proposed intermediate sphincter at the level of the angular notch of the stomach. While the thickening of the circular muscle may indicate the commencement of the pyloric antrum, true functional sphincteric activity distinct from the other peristaltic contractions of the stomach is not observed although some of these may in fact temporarily close off the antrum from the remainder of the stomach lumen. Synonym: antral sphincter, midgastric transverse sphincter, sphincter antri, sphincter intermedius, sphincter of antrum, sphincter of gastric antrum. (05 Mar 2000) |
| artificial sphincter | A sphincter produced by surgical procedures to reduce speed of flow in the digestive system or to maintain continence of the intestine. (05 Mar 2000) |
| basal sphincter | The thickening of the circular muscular coat at the base of the ileal papilla at the terminal ileum. Synonym: sphincteroid tract of ileum. (05 Mar 2000) |
| bicanalicular sphincter | A sphincter encircling two canals, such as the terminal portions of the common bile duct and the main pancreatic duct. (05 Mar 2000) |
| Boyden's sphincter | Smooth muscle sphincter of the common bile duct immediately proximal to the hepatopancreatic ampulla; it is this sphincter that controls the flow of bile in the duodenum. Synonym: musculus sphincter ductus choledochi, Boyden's sphincter, choledochal sphincter, sphincter muscle of common bile duct. (05 Mar 2000) |
| canalicular sphincter | A sphincter located somewhere along the course of an organ, a tube, or a duct, as opposed to ostial sphincter. (05 Mar 2000) |
| macroscopic sphincter | A sphincter visible to the naked eye. (05 Mar 2000) |
| palatopharyngeal sphincter | A constant band of the superior pharyngeal constrictor muscle which sweeps posteriorly from the anterolateral part of the superior surface of the palatine aponeurosis. It creates a visible ridge when the superior constrictor is contracted, meeting the elevated soft palate to seal off the pharyngeal isthmus during swallowing. Synonym: pharyngeal ridge, sphincter of the pharyngeal isthmus, velopharyngeal sphincter. (05 Mar 2000) |